I moved your post over from the poorly named Community Help forum, which is for getting help using this forum system, to a better forum, PSE.
Which version did you purchase e.g. full or upgrade?
After installation there are usually two choices; start trial or Licence/Activate.
If you click trial the software can be used free for 30 days.
If you click to licence/activate you are asked to sign-in and enter your product serial number.
Many thanks for answer. Unfortunatelly it is a not solution because I can't see just these two options after i choosen language and country I leave. After this screen I have the next one which is designed to loading photo editor. Then I clik on photo editor button and (as I understand?) I should see the next screen with two options (trial or licence). But after clicking the software is just starting to do something with information that workspce of Adobe photoshop elements is just loading. It lasts about 10-15 seconds and it is stopping without any result. I put printscreen described stage. I can't do nothing more. What If I ask you again to answer.
Your printscreen shows that the Editor application is launching. Does it not open? Do you not see a separate icon on the taskbar?
And this is a problem. I can't see next screen. There is no open any other icone/screen. There is any icone on the taskbar. I can't move to next step.
Try launching directly from Program Files. Go to:
C:\Program Files\Adobe\Photoshop Elements 2020
Scroll down to the files starting with “P” and double-click on PhotoshopElementsEditor (the application)